Two cases of sinus rhythm with ventricular extrasystoles are reported in which extrasystoles arising from the same focus obey the rule of "comcealed bigeminy" and the "rule of bigeminy". In a comparatively rapid sinus rhythm, shortening of the sinus cycle favors the appearance of extrasystoles, and the extrasystoles obey the fule of "concealed bigeminy"; namely, sinus impulses intervene between...

Concealed conduction into accessory atrioventricular pathways has been postulated to explain variability of R-R intervals during atrial fibrillation in patients with Wolff-Parkinson-White syndrome. We examined the occurrence of concealed conduction into atrioventricular pathways using extrastimulus techniques in 26 consecutive patients undergoing electrophysiologic studies for the Wolff-Parkins...

This report presents a verapamil-sensitive atrial tachycardia, mid-atrium septum activating the earliest. Concealed entrainment was obtained at noncoronary aortic sinus (NCS), where the local activation was delayed compared to mid-septum. The tachycardia was successfully ablated at NCS. The entrance of the slow conduction zone was located at NCS.

In patients with atrioventricular (A-V) nodal re-entrant paroxysmal supraventricular tachycardia (PSVT), atrial extrastimulus technique frequently reveals discontinuous A1-A2, H1-H2 curves suggestive of dual A-V nodal pathways. To further test the hypothesis that these curves in fact reflect dual A-V nodal pathways, a ventricular extrastimulus (VS) was coupled either to A2 at a fixed A1-A2 inte...

The linking phenomenon is an electrophysiological phenomenon of conduction between 2 different pathways, such as bundle branches, atrioventricular node (AVN) and accessory pathways. The present study used electrophysiological studies to investigate this phenomenon in 14 patients with dual AVN pathways. Decremental ramp pacing at intervals of 10 ms was carried out in high right atrium until the ...

An electrophysiologic study followed by transcatheter radiofrequency ablation therapy was performed in two adult patients with a permanent form of junctional tachycardia. Both patients had no structural heart disease and exhibited a normal resting ECG. The P wave during tachycardia was negative in leads 1, 3, and aVF, biphasic over V6, and positive in V1 and aVL in both patients, while the P-R/...

BACKGROUND The aim of this study was to evaluate the indications, results and complications of radiofrequency ablation (RFA) and transcatheter cryoablation (TCA) in neonates and infants with incessant drug-resistant supraventricular tachycardia (SVT). METHODS Out of 225 patients who underwent RFA and TCA at our center between January2010 and February 2012, 5 patients under the age of 1 (4 mal...

OBJECTIVES This study evaluates whether contrast-enhanced (CE) cardiac magnetic resonance (CMR) can be used to identify critical isthmus sites for ventricular tachycardia (VT) in ischemic and nonischemic heart disease. BACKGROUND Fibrosis interspersed with viable myocytes may cause re-entrant VT. CE-CMR has the ability to accurately delineate fibrosis. METHODS Patients who underwent VT abla...